Mitochondrial tRNA(leu)(UUR) gene mutation and the decreased activity of cytochrome c oxidase in preeclampsia.

To explore the roles of mitochondria tRNA(leu)(UUR) gene mutation at nucleotide 3243 and the activity of cytochrome c oxidase in pathogenesis of preeclampsia, 57 patients with preeclampsia and 60 normotension pregnancy women were screened for tRNA(leu)(UUR) nt3243 A-->G mutation with the method of polymers chain reaction (PCR) and restriction fragment length polymorphism. Cytochrome c oxidase activity was determined by measuring the rate of cyanide-sensitive oxidation of reduced cytochrome c using luminosity photographer. The results showed that cytochrome c oxidase activity was significantly lower in the preeclampsia group (0.30 +/- 0.39/min, n = 32) than that in the controls (0.73 +/- 0.54/min, n = 26, P < 0.01). The mitochondria DNA mutation at position 3243 was not found in our series. The results suggested that the decreased activity of cytochrome c oxidase might impair the energy production, leading to the mitochondria dysfunction and placenta dysfunction in preeclampsia patients. Mitochondria dysfunction may be involved in the pathogenesis of preeclampsia. The mutation of mitochondria DNA may not be the common contributor of preeclampsia in our series.